Wellhead constructions



Jan. 11, 1966 C. R. NEILON ETAL WELLHEAD CONSTRUCTIONS 4 Sheets-Sheet 1Filed March 11, 1965 Jan. 11, 1966 c. R. NEILON ETAL 3,223,715

WELLHEAD CONSTRUCTIONS Filed March 11, 1963 4 Sheets-Sheet z m W? 9 a wmmlmfimfi n m a a a o m W A W 7 m l "Y 0 m mwuw W 7 n M all 2 Claude R.Neilon William W. Word,Jr.&

Michael A. walker BY Z! Q! g g ATTORNEYS Jan. 11, 1966 c NElLON ETAL3,228,715

1966 c. R. NEILON ETAL 3,223,715

WELLHEAD CONSTRUCTIONS 4 Sheets-Sheet 4 Filed March 11, 1963 F GINVENTORS Claude R.Ne||on William W. Word,Jr.& Michael A.Walker FIG..5.BY a ATTORNEYS United States Patent 3,228,715 WELLHEAD CONSTRUCTIONSClaude R. Neilon, William W. Word, Jr., and Michael A.

Walker, Houston, Tex., assiguors to Armco Steel Corporation, Middletowu,Ohio, a corporation of Ohio Filed Mar. 11, 1963, Ser. No. 264,195 7Claims. (Cl. 285313) This invention relates to wellhead constructionsand, more particularly, to such constructions which are especiallyadapted for installation at substantial depths under water.

In recent years, the petroleum industry has found it practical to drillwells in earth formations lying beneath bodies of water of aconsiderable depth. In present-day practice, it is not unusual to drillwells in formations under water up to several hundred feet deep, anddrilling operations have already been carried out under thousands offeet of water. In underwater wells generally, and particularly in manysubsea operations, the site of the wellhead is at such a depth as topreclude diving operations, unless complicated and expensive divingvessels, operated in conjunction with a caisson or the like, areemployed. There is accordingly an active demand for a practical wellheadconstruction which can be successfully installed without the presence ofa human operator at the wellhead site.

Drilling and production requirements are such that underwater remotelyassembled wellhead constructions require at least one, and frequentlymore than one, coupling between upright wellhead body members.Typically, there must at least be one wellhead body member serving tosupport casing and tubing strings, and at least one Christmas tree bodymember. Such body members are separately installed and must, of course,be coupled together in fluid-tight relation. Though it might at firstappear that the provision of remotely operated couplings suitable forjoining the wellhead body members would not be an unusually diiiiculttask, the problem has proved to be extremely diflicult because of theadverse conditions encountered in making underwater installations.

In a typical underwater driling operation, for example, a lower wellheadbody member may be used to support the casing strings and, ultimately,the tubing string or strings, and the next higher members of thewellhead may be a coupling and the blowout preventer stack, a riserbeing coupled to the blowout preventer stack. In such an installation,the blowout preventer stack is typically 1015' in height and representsa mass on the order of 50,000 pounds. The riser may be of tubing havingan innerdiameter of 13% inches and a length of 150 feet, for example.The supplier of the wellhead components must, therefore, providecouplings which are capable of handling truly great loads. This problemis greatly complicated by the fact that, when the components areassembled at the wellhead site, the assembly will be subjected tocurrents up to eight knots and stronger, with the strength of thecurrents varying at different depths and the direction of the currentsalso varying. Thus, even without considering forces which result fromdrilling and like operations carried out via the equipment, it isobvious that the wellhead will be subjected to tremendous bending forceswhich must be taken across the joint maintained by each coupling.Because of the height of the blowout preventer stack and the riser, thebending couples which may result from wave action and from movement ofthe drilling vessel act through a long moment arm. On the other hand,the opposing couple, provided by the coupling, acts only through a veryshort moment arm equal to the radius of the bore at the coupling plus asmall increment.

In ability of the coupling to provide a joint capable of withstandingthe large bending moments resulting from wave action, for example, canresult in various kinds of wellhead failure, including failure of theseal or seals at the joint, and failure of support elements, evenincluding the body members themselves. The difficulties arising fromsuch failures vary and can be so severe as to require that the well beabandoned. Despite the fact that experimental, semiexperimental andcommercial drilling operations in underwater locations have now beencarried out for a relatively long period, the art has heretofore beenunable to provide a truly satisfactory coupling for remotely assembledwellhead constructions.

The problem of providing a practical coupling in such circumstances ismade more difiicult by the fact that the coupling must maintain asatisfactory joint over a prolonged time period. In the case of acoupling at the base of the Christmas tree, for example, the requirementfrequently is that the joint be maintained for the life of the well. Onthe other hand, it is essential that such couplings be capable of beingreadily disconnected, by remote manipulation, and failure of thecoupling to disconnect can lead to great difiiculties, even requiringabandoning the well.

A general object of the invention is to provide, in wellheadconstructions of the type described, improved coupling means which canbe operated remotely and is capable of establishing joints etfective towithstand the forces encountered even in deep water installations.

Another object is to provide, in an underwater wellhead construction,means for coupling wellhead members together in such fashion that atruly adequate axial clamping force is established at the joint betweenthe coupled members.

A further object is to provide such a wellhead construction wherein thecoupling can be operated, after the joint has been established, toassure that the axial clamping force at the coupled joint will bemaintained during use of the wellhea Yet another object i to provide animproved, fully practical power operated coupling means for underwaterwellhead constructions.

A still further object is to devise a remotely operated wellheadcoupling structure which provides maximum assurance of successfulestablishment and disengagement of the coupled joint solely by remoteoperation, without requiring diver assistance.

Another object is to provide a remotely operated wellhead couplingstructure including power operated means for establishing the coupledjoint and wherein the power operated means itself assures againstaccidental disengagement of the coupling.

A further object is to devise such a structure wherein metal orequivalent sealing rings can be employed under axial pressure toestablish effective sealing of the joint.

A still further object is to provide a remotely operated, power actuatedcoupling for wellhead members so arranged that the powcr actuated meansserves both to accomplish engagement and disengagement of the coupling,and purely mechanical means is available for effecting disengagement ofthe coupling in the event that poweractu'ated disengagement cannot beaccomplished.

In order that the manner in which these and other objects are attainedin accordance with the invention can be understood in detail, referenceis bad to the accompanying drawings, which form a part of thisspecification, and wherein:

FIGS. 1 and 2 are views, partly in side elevation and partly in verticalsection, of a portion of a wellhead apparatus constructed in accordancewith one embodiment of the invention, the two views showing parts of theapparatus in different positions;

FIG. 3-is a view, partly in top plan and partly in trans verse section,taken generally on line 3-3, FIG. 1; and

FIG. 4 is an enlarged fragmentary vertical sectional view illustratingdetails of locking mechanism employed in the apparatus of FIGS. 1-3.

FIG. 5 is a vertical sectional view of one half of a wellhead apparatusconstructed in accordance with another embodiment of the invention;

FIG. 6 is a transverse sectional view taken on line 6-6, FIG. 6; and 1FIG. 7 is a fragmentary vertical sectional view showing certain elementsof the structure of FIG. 5 in different operational positions.

Turning now to the drawingsin detail, and first to FIGS. 1-4, it will beseen that this embodiment of the invention comprises a lower body member1, such as a casing head, an upper body member 2, such as a tubing head,and a lock actuating member 3 in the form of a two-piece sleeve. Sincethe invent-ion is concerned primarily with the manner in which the bodymembers 1 and 2 are engaged and locked together, only the upper portionof member 1 and the lower portion of member 2 are shown, it beingunderstood that the remainder of the wellhead construction can be ofconventional form.

Body member 1 is generally cylindrical, having an upright plaincylindrical through bore 4. At its top, body member 1 has a downwardlyand inwardly tapering frustoconical annular surface 5 which extendstransversely of the body member and is concentric with bore 4. The topedge of surface 5 joins a circular end surface or seat 6 lying in aplane at right angles to the axis of bore 4. The radial width of surface6 is less than that of the relatively thick wall 7 of the body member,and a downwardly and outwardly slanting shoulders surrounds that endportion of the member which presents surface 5.

Body member 1 has an outer cylindrical surface portion 9, extendingdownwardly from shoulder 8, and another outer cylindrical surfaceportion 10, portion 10 having a slightly larger diameter than portion 9and the two portions being separated by a transverse annular upwardlyfacing shoulder 11.

Below shoulder 8, surface portion 9 of the lower body member isinterrupted by an outwardly opening transverse annular locking groove12. Groove 12 is defined by a downwardly and inwardly slanting top wall13, a cylindrical inner wall 14 coaxial with bore 4, and a downwardlyand outwardly slanting lower wall 15.

Below shoulder 11, body member 1 carries a locater pin 16 projectingradially outwardly from surface portion 10.

Upper body member 2 has an upright through bore 17 the lower end ofwhich is encircled by a circularly extending transverse flange 18 havinga downwardly and inwardly tapering frusto-conical outer surface 19.Surrounding flange 18, and joining surface 19 at the root thereof, is acircularly extending flat surface or seat 20 lying in a plane at rightangles to the axis of bore 17. The diameter of surface 19 issubstantially less than the diameter of surface 5 so that, when bodymember 2 is lowered toward body member 1, with bores 4 and 17 aligned,flange 18 can enter the space defined by surface 5, surface 20 coming torest in face-to-face engagement with end surface 6, as will be clearfrom FIG. 2.

The anglejat which frusto-conical surface 19 slants inwardly anddownwardly is materially greater than the corresponding angle forsurface 5. A metal sealing ring 21 embraces surface 19, being held inplace by a retaining ring 22 secured to the tip of flange 18, as byscrews 23. Sealing ring 21 is advantageously of the type disclosed inUS. Patent 2,687,229, issued August 24, 1954, to Laurent. and is made ofa metal materially softer than that used in fabricating body members 1and 2. The inner and outer surfaces of sealing ring 21 are disposed toat least generally conform to surface 19 and surface 5, respec tively,Accordingly, as flange 18 ent rs the sp ce defined by surface 5, thesealing ring is wedged between surfaces 5 and 13, the sealing ring beingsufiiciently deformed, when surface 20 comes into engagement withsurface 6, to assure a good fluid-tight seal between the two bodymembers.

Upper body member 2 is provided with an integral cylindrical dependentskirt indicated generally at 24 and disposed concentrically with respectto bore 17 and surface 19. Skirt 24 projects for a substantial distancebelow flange 18 and terminates in a downwardly and outwardly taperingfrusto-conical guiding surface 25. Immediately above surface 25, skirt24 has an inner diameter slightly greater than the diameter of surface10 of body member 1,

so that a distinct clearance 26 will be afforded between surface 10 andthe inner surface of skirt 24 when the upper body member is seated onthe lower body member. When the two body members are engaged in thisfashion, the inner surface of skirt 24 extends in plain cylindricalfashion to apoint well above shoulder 11. Here, skirt 24 is providedwith a downwardly facing, inwardly extending shoulder 27. Above shoulder27, the inner surface of the skirt is cylindrical and of such diameteras to closely embrace surface portion 9. of body member 1. Immediatelyabove shoulder27, skirt 24 is provided with an inwardly opening,transversely extending groove in which is disposed a sealing ring 28.

Assuming that body member 2 is so manipulated as to approach the top ofbody member, 1 while bores 4 and 17 are in at least approximatealignment, guiding surface 25 will engage the top of the lower bodymember and cause the upper body member to be properly centered. .Skirt24 then descends along surface portions 9 and 10 of the lower bodymember, sealing ring 28 engaging surface portion 9 in substantiallyfluid-tight relation. Assuming that the installation is being made underwater, it is clear than an initial body of water will be trapped in theannular space 29 between shoulders 11 and 27, this body of. water beingforced out through cleanance 26 as the upper body member descends.Accordingly, a dash-pot action occurs, causing the movement of the upperbody member to be slowed to such an extent that, as the upper bodymember comes into final, seated position, the sealing ring 21 will notengage surface 5 with suflicient force to cause damage to either thesurface 5 or the ring.

Above the location of flange 18, skirt 24 extends as a thickened portion29 of the main Wall 31) of upper body member 2. Skirt 24 has upper andlower coaxially arranged plain cylindrical outer surfaces 31 and 32, respectively, separated by an intermediate, outwardly projecting, annularportion 33. Surfaces 31 and 32 have the same diameter while intermediateportion 33 presents an outer surface of materially larger diameter.Upper surface portion 31 joins intermediate portion 33 at an outwardlyprojecting, upwardly facing transverse annular shoulder 34, FIG. 1,while portion 32 joins intermediate portion 33 at an outwardlyprojecting, downwardly facing transverse annular shoulder 35.

Lock actuating sleeve 3 comprises a lower portion 36 and an upperportion 37. Portion 36 includes a cylindrical main body 38 which.slidably embraces intermediate portion 33 of skirt 24 and is providedat its top with a fiat, transversely extending annular end face 39 andat its bottom with an inwardly projecting transverse annular flange 4ti.Portion 37 is in the form of a ring having a fiat bottom face engaged inface-to-face contact with the top end face of body 3-8, the ring beingsecured to the body in any suitable fashion, as by studs. 41. While theouter face of portion 37 extends as a continuation of the outer face ofbody 38, portion 37' projects inwardlyto such 'a degree that thecylindrical inner face thereof closely embraces surface 31 of skirt 24.Similarly, the cylindrical inner face of bottom flange 40 closelyembraces surface 32 of skirt 24. It will thus be apparent that, assumingthat the actuating s eeve 3 is not otherwise restrained, the sleeve canbe moved, axially of the body member 2, between an upper position,illustrated in FIG. 1, and a lower position, such as that shown in FIG.2. When the sleeve is in its uppermost position, flange 41? engages thebottom of intermediate portion 33 of skirt 24, and there is acylindrical space 42, FIG. 1, between the top of intermediate portion 33and ring 37. In lowered positions of sleeve 3, there is a cylindricalspace 43, FIG. 2, between the bottom of portion 33 and flangeImmediately above the bottom of ring 37, the inner face of the ring isprovided with a transverse annular groove accommodating a sealing ring44 engaged with upper surface portion 31 of skirt 24. The top of body 38is provided with an annular upwardly opening groove accommodating asealing ring 45 which is effective to seal between body 38 and thebottom face of ring 37. Immediately below its upper end, intermediateportion 33 of the skirt is provided with a transverse annular groove inwhich is disposed a sealing ring 46 effective to provide a seal betweenthe skirt and body 38.

Immediately above its lower end, intermediate portion 33 of the skirthas a transverse annular groove accommodating a sealing ring 47 whichseals between the skirt and body 38. Bottom flange 46 is provided withan inwardly opening groove retaining a sealing ring 48 which is engagedwith lower surface portion 32 of the skirt.

Skirt 2.4 is provided with two bores 49 and 56 extending downwardly fromthe top of the skirt and communieating respectively with spaces 42 and43. Bores 49 and 50 are provided at their upper ends with suitablefittings (not shown) for connection of flexible hydraulic conduits toextend between the operators position and the remote location of theinstallations.

It is accordingly apparent that spaces 42 and 43, being sealed influid-tight relation for all positions of the actuating sleeve 3, areeffective as expansible chambers, and that the bores 49 and 56 can beemployed to supply and exhaust fluid under pressure to the spaces 42 and43 in order to accomplish movement of actuating sleeve 3 upwardly ordownwardly, as desired. It will be understood that the hydraulic linesconnected to bores 49 and 50 can be controlled by suitable valves andthus selectively connected to act either to supply fluid or ex haustfluid, depending upon the direction of motion of the sleeve desired.

In a location spaced below flange 18, skirt 24 is provided with aninwardly opening, circularly extending, transverse groove 51. Thelocation of groove 51 is such that, when sealing ring 21 is properlyengaged with surface 5, and surfaces 6 and 29 are in mutual engagement,groove 51 will be substantially aligned with groove 12. Groove 51 has arectangular transverse cross section. In the same location, skirt 24 isprovided with four angularly spaced, radially extending openings 52 eachcomprising an outer cylindrical portion 53 of larger diameter and ashort inner cylindrical portion 54 of smaller diameter. Portions 53 openthrough the outer surface of intermediate portion 33 of the skirt, whileportions 54 open inwardly intogroove 51.

For each of openings 52, there is provided a lock member indicatedgenerally at 55. All four of the lock members are identical and only onewill be described in detail. As seen in FIGS. 1 and 3, the lock member55 is made in two parts, one being an arcuately extending lockingsegment 56 and the other being a cam extension comprising a cylindricalstem 57 and a cam follower portion 58, portions 57 and 58 being integralwith each other.

Locking segment 56 has arcuate inner and outer faces 59 and 60,respectively, and flat upper and lower faces 61 and 62, faces 61 and 62being spaced by a distance such that they are disposed. in slidableengagement with the upper and lower walls of groove 51, respectively.Faces 59 and 61 are joined by a downwardly and inwardly slanting face 63disposed at the same angle as upper wall 13 of groove 12. Faces 59 and62 are connected by an upwardly and inwardly slanting face 64 disposedat the same angle as lower wall 15 of groove 12.

At its center, segment 56 is provided. with a stud portion 65, FIG. 4,which projects radially outwardly and is exteriorly threaded. Stem 56 isprovided at its inner tip with an axially aligned interiorly threadedbore in which stud 65 is threadedly engaged to secure the two parts ofthe lock member 55 rigidly together. As seen in FIG. 1, stem 57 projectsthrough the corresponding opening portion 54 and thence outwardlythrough the larger opening portion 53. The wall of each portion 54 isprovided with an inwardly directed transverse annular groove in which isretained a sealing ring 66 disposed to engage the outer surface of stem57 to afford a fluid-tight seal between groove 51 and the correspondingopening 52.

Cam follower portion 58 has a circular transverse cross section, thediameter thereof being only slightly smaller than the diameter ofportion 53. The outer tip of portion 53 is spherical. At its inner end,portion 58 presents a flat annular surface, lying in a plane at rightangles to the longitudinal axis of stem 57, this flat annular surfacebeing opposed to and spaced from the shoulder between opening portions53 and 54. A helical compression spring 67 is engaged between the flatannular inner face of portion 57 and the shoulder just mentioned andserves to bias the lock member 55 normally to the position seen in FIG.1, with the lock segment 56 retracted and housed completely in groove 51and cam follower portion 58 projecting outwardly from the outer surfaceof intermediate portion 33 of the skirt. Thus, when all of the lockmembers 55 occupy the normal position just described, the lock membersdo not interfere in any way with lowering of the skirt over the upperend portion of body member 1.

At a point intermediate its ends, body 38 of lower portion 36 of thelock actuating sleeve is provided with an inwardly opening transversecam groove indicated generally at 68. As best seen in FIG. 4, cam groove68 has a transverse bottom shoulder 69, a plain cylindrical surfaceportion 70, an intermediate frusto-conical surface portion 71 whichslants upwardly and inwardly at a larger angle, and an upperfrusto-conical surface portion 72 which slants upwardly and inwardly ata smaller angle. Cam groove 68 is so located that, when flange 40engages the bottom end of intermediate portion 33 of the skirt, thecylindrical cam surface portion 70 is disposed opposite openings 52, sothat biasing spring 67 can urge the lock members outwardly into theirnormal positions, cam follower portions 58 engaging the cam surface 70.Upon downward movement of the lock actuating sleeve 3 on skirt 24, camfollower portions 58 are engaged successively by cam surface portions 71and 72. Since surface portion 71 is disposed at a relatively largerangle, engagement of the cam follower portions with this surface willresult in a relatively large radial inward movement of the lock members.Such movement cannot occur, unless the groove 51 has been substantiallyaligned with groove 12, it being understood that this initial radialinward movement of the lock members serves to accomplish a preliminaryengagement of segments 56 in groove 12. Further downward travel of lockactuating sleeve 3 causes surface portion 72 to ride over cam followerportions 58 and results in further radial inward movement of the lockmembers, this further movement being small as compared to the initialmovement resulting by engagement of the cam follower portions with camsurface 71. The purpose of the two-stage cam actuation of lock members55 will be discussed in detail hereinafter.

Adjacent the top of thickened portion 29, there are provided fouroutwardly opening recesses 73 spaced equally about the central axis ofbody member 2. Recesses 73 are radially directed and there is providedin each recess a latch element indicated generally at 74 and biasedoutwardly by a compression spring 75. The latch element-s are identicaland only one will be described. The inner end portion of latch element74 has a rectangular transverse cross section matching that of thecorresponding recess 73, so that the latch element is slidable in therecess and is restrained to a predetermined radial orientation. Thelatch element has a flat outer tip portion 76 disposed in a plane atright angles to the axis of body member 2. The upper surface of thelatch element includes a downwardly and outwardly slanting portion 77which joins the fiat upper face of tip 76. Similarly, the lower surfaceof the latch element includes an upwardly and outwardly slanting portion78 which joins the lower face of tip 76. The inner face of ring 37 isprovided with an inwardly opening, relatively shallow transverselyextending groove 79 having a flat upper wall lying in a plane at rightangle-s to the central axis of actuating sleeve 3. As will be clear fromFIG. 1, when flange 40 engages the shoulder presented by the bottom endof intermediate portion 33 of skirt 24, groove 79 is so located thatoutward movement of latch elements 74 will result in engagement of theupper faces of tips 76 beneath the fiat upper wall of groove 79, so thatthe entire actuating sleeve 3 is retained in itsuppermostposition by thelatch elements. The radial length of the latch elements, and thecharacteristics of the biasing springs 75, is such that the biasingsprings are effective to move the latch elements outwardly through adistance sufficient to cause tips 76 to engage properly with groove 79.FIG. 1 illustrates the actuating sleeve latched in its uppermostposition and it will be understood that this is the position in whichthe sleeve is disposed when upper body member 2 is lowered to engagebody member 1.

I It will be understood that the latch elements 74, springs 75 andgroove 79 cooperate to form a releasable latch for retaining the sleeve3 in its uppermost position. In accordance with this embodiment of theinvention, release of this latching arrangement is accomplishedautomatically in response to seating of the upper body member on thelower body member. Adjacent each of the recesses 73, thickened portion29 is provided with a downwardly and inwardly slanting bore 80. All ofbores 80 are identical and are arranged in identical fashion withrespect to its adjacent recess 73, and only the single bore seen in FIG.1 will be described in detail. The lower end portion of bore 80 is ofsmaller diameter, while the remaining upper portion of the bore is oflarger diameter, a transverse shoulder 81 being provided between the twobore portions. The angle of inclination of the bore is such that, whenbody member 2 is aligned coaxially with body member 1, as seen in FIG.1, the axis of bore 80 extends at right angles to the downwardly andoutwardly slanting frusto-conical surface 8 at the top of body member 1.

Slidably disposed in bore 80 is a latch release pin 82 having anintermediate portion 83 of larger diameter and end portions 84 and 85 ofsmaller diameter. An exteriorly threaded plug 86 is provided in theupper end of bore 80 and has a central bore accommodating upper portion84 of the latch release pin. A helical compression spring is engagedbetween the upper end of intermediate portion 83 of the pin and thelower face of plug 86, so that the spring 87 serves to bias the pindownwardly until the lower end of intermediate portion 83 engagesshoulder 81. With the latch release pin in this normal position, lowerend portion 85 thereof projects well below the tip of flange 18, whileupper end portion 84 projects a short distance above the lower wall ofthe adjacent recess 73. Hence, biasing spring 75 forces the latchelements '74 outwardly until lower slanting surface portion 78 of thelatch element is engaged against the tip of upper portion 84 of thelatch release pin. With the parts in these positions, latch element 74projects outwardly far enough t engage beneath the upper wall of groove79.

The locations and inclinations of bores 80, and the dimensions of latchpins 82, are such that, with body member 2 spaced slightly above bodymember 1, and with the latch pins occupying their normal positions asabove described, the lower tips of the latch pins are arranged in acircle which registers with surface 8. Hence, lowering of the upper bodymember into proper seated relation will cause the latch pins to comeinto engagement with surface 8, so that all of the latch pins are forcedupwardly in their respective bores 80. Such upward movement of the latchpins causes the upper tips thereof to ride along the respective upwardlyand outwardly slanting surfaces 78 of the latch elements. Hence, thelatch elements are simultaneously shifted radially inwardly to such adegree that tips 76 are withdrawn completely from groove 79 and locksleeve 3 is accordingly freed for movement downwardly relative to skirt24.

The lower portion of the inner surface of skirt 24 is provided with anaxially extending locator groove 88 having an outwardly flaring openlower end and so dimensioned as to slidably receive locator pin 16. Thecombination of pin 16 and groove 88 serves automatically 'to orientupper body member 2 in a given rotational position (about the commonaxis of the two body members') .so that wellhead elements (not shown)will be properly oriented. It is to be noted that no special rotationalorientation is required for proper operation of the locking means ofthis invention or for proper operation of the latching means, sincelocking groove 12, cam groove 68 and latch groove 79 are all continuousannular grooves which serve their purposes in any relative rotationalpositions of body member 1, skirt 24 and sleeve 3.

Those skilled in the art will understand that lower body member 1 isfirst installed at the top of the borehole in conventional fashion,being fixed in place rigidly, and

that this installation may be made under water at depths up to manythousands of feet. Body member 2 is lowered toward the top of bodymember 1 in any conventlonal fashion. For this phase of the operation,guide lines (not shown) of a type now well known in the art areordinarily employed to achieve approximate centering of body member 2relative to body member 1, so that, as the upper body member approachesits final position, frusto-conical guiding surface 25 engages the top ofbody member 1 and accomplishes precise alignment of body member 2coaxially with body member 1. It will be understood that, when bodymember 2 is prepared for lowering into place, sleeve 3 is in itsuppermost position and is retained in that position by engagement oftips 76 of latch elements 74 beneath the upper shoulder of groove 79,pins 82 being biased to their lowermost positions, seen in FIG. 1, bysprings 87. Accordingly, cam groove 68 is so disposed that lock members55 are allowed to occupy their normal outermost positions, leaving theinternal bore of skirt 24 free and unimpeded to slide over the upper endportion of lower body member ll.

As sealing ring 28 comes into engagement with surface 9, a dash-dotaction occurs, the water trapped between shoulders 11 and 27 beingforced out through clearance 26. This dash-pot action slows the downwardtravel of the upper body member sufliciently to assure that parts whichcome into abutting engagement during final movement of the upper bodymember will not be damaged. As the dash-pot action commences, the upperbody member is rotated until pin 16 enters groove 88. Downward motion ofthe upper body member continues, the lower tips of pins 82 coming intoengagement with surface 8, so that continued descent of body member 2causes the pins 82 to be raised, the upper ends of the pins then camminglatch elements 74 inwardly by reason of the surfaces 78 of the latchelements. Tips 76 of the lat h elements are thus withdrawn from groove79, freeing sleeve 3 for downward movement relative to skirt 24. Sincesleeve 3 is of very substantial weight, downward movement thereof maycommence by gravity. In this connection, it is to be noted that thesleeve 3 may weigh several thousand pounds for wellhead constructions ofconventional size. Initial downward movement of the sleeve at this timeis not disadvantageous, since such movement will not occur until groove51 has passed below surface 8, so that such initial inward movement oflock members 55 as may result can only cause the inner faces 59 of thelocking segments to engage surface 9. If desired, gravitational movementof sleeve 3 can be prevented by maintaining adequate hydraulic pressurein cylindrical space 42.

Further downward movement of upper body member 2 brings metal sealingring 21 into engagement with surface 5, the relatively great weight ofthe upper body member causing ring 21 to be engaged between surfaces and19 in wedging fashion so that a good fluid-tight seal is obtainedbetween the two body members. The positions of surfaces 5 and 19 and theshape: and dimensions of ring 21 are such that, as the sealing ringbecomes finally seated, when adequate clamping force is applied tomembers 1 and 2, surface 20 is allowed to come into full face-to-faceengagement with surface 6, so that upper body member 2 is seateddirectly on lower body member 1.

When upper body member 2 has thus been seated on the lower body member1, groove 51 is, because of the relative dimensions of the parts of theapparatus, substantially aligned with lock groove 12. As seen in FIG. 4,it is advantageous that, at this stage of the operation, the upper wallof groove 51 be disposed slightly above the outer edge of wall 13 oflock groove 12. Hydraulic pressure is now applied via bore 50. Thepressure fluid enters betwen flange 40 and shoulder 35. Accordingly,sleeve 3 is forced downwardly. Downward movement of sleeve 3 firstcauses cam surface portion 71 to slide simultaneously over the outerends of all four cam follower portions 58, causing lock members 55 to beforced radially inwardly, with segments 56 entering groove 12. Furtherdescent of sleeve 3 causes the uppermost cam surface portion 72 toengage all of the cam follower portions 58. Since cam surface portion'72 is disposed at a relatively smaller angle, and is of a smalleraverage diameter than portion 71, a correspondingly smaller radialinward movement of the lock members 55 results. As seen in FIG. 4,descent of only a part of cam surface portion 72 past the point ofengagement with cam followers 58 causes surface portion 63 of segments56 to be solidly wedged beneath upper wall 13 of groove 12.

Such wedging action applies an axially clamping force effective toseccre body members 1 and 2 rigidly together, with surfaces 6 and 20engaged. It is to be noted that application of this claim-ping forceinvolves a simple and direct load circle including the upper end portionof body member 1, the segments 56, and the integral structure comprisingthe upper portion of skirt 24 and the lower portion of body 2.Independent of the load circle involved in energization of sealing ring21, the clamping load circle is such that the clamping force does notact through threaded or bolted joints, and the opportunities forloosening of the coupling once segments 56 are engaged in groove 12 areminimized.

Even though surfaces 5 and 20 are clamped in direct engagement, and theclamping load circle mainly involves solid metal bodies, it is stillhighly advantageous to provide for increasing of the wedging action ofsegments 56 in groove 12 subsequent to installation of the coupling. Inthis regard, it is to be noted from FIG. 4 that, after the coupling hasbeen engaged initially, space still remains between inner wall 14 ofgroove 12 and faces 59 of segments 56 to allow further radial inwardmovement of the locking members and space also still remains belil tweenportion 33 and ring 37 and, therefore, additional wedging action betweensurfaces 63 and wall 13 can be accomplished as a result of furtherdescent of actuating sleeve 3, causing further travel of cam surfaceportion 72 over the follower portions 58. At least to some degree, thisfurther downward movement can be allowed to result solely bygravitational action, particularly where the weight of sleeve 3 islarge. Alternatively, this additional movement can be accomplishedpositively, simply by increasing the hydraulic pressure applied via boreto cylindrical space 43.

The ability to provide additional wedging action between surfaces 63 andwall 13 after the wellhead has been installed is particularly important,since the wellhead assembly can be satisfactory only if the highclamping force applied to body members 1 and 2 is preserved. During useafter installation, the wellhead is subjected to vibration, shock andthe severe bending moments hereinbefore discussed and, in manyinstances, the high clamping force established when the coupling is madeup will not persist unless further wedging of the segments in thelocking groove can be effected.

Surface 72, constituting a slow taper portion of cam groove 68, alsocoacts with followers 58 to provide a frictional l=ock-down capable ofpreventing accidental upward displacement of ring 3. In this regard,surface 72 tapers toward the axis of the assembly at an angle so smallthat the tangent thereof is materially less than the coefiicient offriction between surface 72 and followers 58 under the conditions ofpressure and lubrication employed. Thus, for example, surface 72 canextend at an angle of approximately 445, to the wellhead axis. With ring3 and followers 58 formed of steel, and with suitable lubrication, thecoeflicient of friction at surface 72 is decidedly greater than thetangent of the angle at which surface 72 is disposed, and even ratherlarge upward forces on ring 3 are successfully resisted by thefrictional engagement between the followers 58 and surface 72.

It will be apparent that, at any time after installation, the two bodymembers can be unlocked simply by relieving the hydraulic pressure inchamber 43 and applying adequate hydraulic pressure via bore 49 tochamber 42. This results in upward movement of actuating sleeve 3relative to skirt 24 and this movement can be continued until flange 40engages shoulder 35. Such upward movement brings cam grooves 68 againinto full registry with openings 52, so that springs 67 can again movelocking members radially outward to an extent such that segments 56 arecompletely withdrawn into groove 51. Such withdrawal of locking members55 allows upper body member 2 to be raised and detached from bodymember 1. As body member 2 is moved upwardly away from the top of bodymember 1, pins 82 are again moved downwardly by springs 87 and, assumingsleeve 3 to be held in its uppermost position, the tips 76 of latchingelements 74 again engage in groove 79 to latch sleeve 3 in its raisedposition.

Use of the exterior ring 3, coacting with skirt 24 to form chambers 42and 43, offers distinct advantages. This construction can gomanufactured with relative ease and at relatively low cost, withoutrequiring that strength be sacrificed. Also, being fully exposed, ring 3can be actuated mechanically to release the coupling in the event offailure of the hydraulic system. In this regard, mechanical actuation ofthe ring 3 can be accomplished with an overshot ring (not shown), orsimply by use of jerk lines (not shown) attached to the ring in anysuitable fashion. Finally, ring 3 in no way interferes with theapplication of the clamping force to memhers I and 2.

FIGS. 5-7 illustrate another embodiment of the invention, again in theform of a wellhead construction comprising a lower body member 101, anupper body member 102 and a locking member in the form of a two piecesleeve 103, an annular member 104 being secured rigidly to and dependingfrom upper body member 102.

Member 101 is a cylindrical tubular member having a through bore 105and, at its top, a transverse annular downwardly and inwardly taperingfrusto-conical surface 106. Surface 106 joins a circular transverselyextending end surface107 lying in a plane at right angles to the axis ofbore 105. The upper portion of member 101 has a plain cylindrical outersurface interrupted by an outwardly opening transverse annular lockinggroove 108 wivichr is spaced below the location of surfaces 106 andUpper body member 102 is generally cylindrical, havmg a through bore109, a flat, circularly extending transverse end face 110, and adependent annular flange 111 which has an'outer downwardly and inwardlyslanting 'frusto-conical surface 171 so disposed as to be spacedconcentrically inwardly from surface 106 when the end face 110 of member102 is seated upon end face 107 of member 101.

'Member 102 has an outwardly projecting annular flange 112 having acylindrical outer face embraced by an uptsanding tubular projection 113on annular member 104. Flange 112 has aflat bottom face and member 104is correspondingly provided with a flat face enclosed by projection 113and disposed to be engaged directly by the bottom face of flange 112.Member 104 is rigidly secured to member 102, as by screws 114.

The main body 115 of member 104 has a plain cylindrical inner surface116 of a diameter to slidably embrace the outer surface of the upperportion of body 101. At its lower end, surface 116 joins an outwardlyand downwardly slanting frusto-conical guide surface 117. In a locationto be aligned with locking groove 108 when member 102 is seated onmember 101, cylindrical surface 116 is interrupted by an inwardlyopening transverse annular groove 118 having flat top and bottom wallsand a cylindrical outer wall. An annular seal 119, retained in asuitable groove provided in surface 116 adjacent surface 117, isemployed to effect a fluid-tight seal between members 101 and -4.

Projection 113 has a cylindrical outer surface 120 terminated at itslower end by an outwardly projecting transverse annular shoulder 121.Shoulder 121 also determines the upper end of a cylindrical outersurface portion 122 of larger diameter than surface 120. At its bottomend, surface portion 122 terminates at the upper wall of an outwardlyopening transverse annular groove 123. Below groove 123, member 104 hasouter cylindrical surface portions 124 and 125 which are separated by adownwardly facing transverse annular shoulder 126, surface portion 124having a larger diameter than does surface portion 125 and a somewhatsmaller diameter than surface portion 122.

Locking sleeve 103 comprises a lower portion 127 and an upper portion128 rigidly secured together, as by screws 129. At its bottom end,member 103 has an inwardly projecting transverse annular flange 130having a grooved cylindrical inner surface, the groove retaining asuitable seal 131. The diameter of the inner surface of flange 130 issuch that the seal 13-1 is maintained in slidable fluid-tight sealingengagement with surface portion 125. Immediately above flange 130,member 103 presents a cylindrical inner surface portion 132 whichclosely embraces surface :portion 124 of member 104. Surface portion 124is provided with a groove immediately above shoulder 126, and a seal 133is disposed in this groove to provide a fluid-tight seal between members103 and 104 at this point. Flange 130, shoulder 126, surface portion 125and surface portion 132 define an expansible chamber, and a suitableduct 134 is provided in member 103 for the supply and exhaust of fluidfrom this chamber.

Immediately above inner surface portion 132, member 103 is provided witha cam groove comprising a cylindrical outer surface portion 135, atransverse bottom wall cylindrical surface of projection 113.

136 and two upwardly and inwardly slanting surface portions 137 and 138.Surface portion 137 joins outer wall and slants inwardly at a relativelylarger angle which may, for example, be 24. Upper slanting surfaceportion 138 joins surface portion 137 and slants inwardly at a markedlysmaller angle which may, for example, be slightly in excess of 4.

Bottom wall 136 of the cam groove does not extend completely to surfaceportion 132 but is terminated by an upwardly directed tubular projection139 which is defined by the upper portion of surface 132, an outer wall140, and a rounded upper edge 141.

Above the cam groove member 103 has an inner cylindrical surface portion142 of a diameter to closely embrace outer surface portion 122 of member104. Surface portion 122 is grooved, immediately below shoulder 121, toaccommodate a seal 143 for effecting a fluid-tight seal between surfaces142 and 122 in this location. At its upper end, member 103 is providedwith an inwardly directed transverse annular flange 144 which presents acylindrical inner surface of a diameter to'closely embrace tubularprojection 113. The inner face of flange 144 is suitably groved toretain a seal 145, so that a fluidtight seal is effected between flange144 and the outer The lower face of flange 144, shoulder 121, surface122 and surface 142 combine to define an expansible chamber with which aduct 146 communicates for the supply and exhaust of pressure fluid.

Groove 118 in member 104 slidably retains a plurality of identicallocking segments 147. Segments 147 are arculate and arranged end-to-endin a circular series, as will be clear from FIG. 6. Each segment 147 hasa flat upper face 148, a flat lower face 149, and an arcuate face 150.Upper face 148 is joined to arcuate face 150 by a downwardly andinwardly slanting face 151 and an upwardly and inwardly slanting face152 is provided between lower face 149 and arcuate face 150. Eachsegment also has an arcuate outer face 153, the distance between faces150 and 153 being somewhat less than the radial depth of groove 118. Theheight of each segment 147 is such that surfaces 148 and 149 slidablyengage the upper and lower walls, respectively, of groove 11%. Grooves118 and 123 are separated by an annular wall 154 provided with aplurality of radially directed cylindrical bores 155, there being onebore 155 for each of the locking segments 147.

Groove 123 slidably accommodates a plurality of 1dentical camfoliowersegments 156 which are equal in number to the locking segments 147.Segments 156 are arcuate and arranged end-to-end in a complete circularseries, as will be clear from FIG. 6. Each segment 156 has a flat uppersurface 157 and a flat lower surface 158 which, at its outer edge, joinsthe downwardly and outwardly slanting arcuate surface 159 of a dependentcam flange 160. The outer face of each follower segment 156 is designedto cooperate with the inwardly facing cam surfaces presented by thelocking sleeve 103. The outer face of each follower segment includes arounded upper portion 161, a downwardly and outwardly slantingintermediate portion 162, and a cylindrical lower portion 163. As willbe clear from FIG. 7, each cooperating pair of locking and followersegments is provided with radially aligned bores 164 and 165,respectively, bore 164 being threaded for engagement with a retainingscrew 166. The follower segment 156 is recessed, as indicated at 167, toaccommodate the head of the retaining screw. A spacer sleeve 168surrounds the screw 166 and has its ends in respective engagement withthe adjacent faces of segments 147 and 156, the diameter of the sleeve168 being such that the sleeve is freely accommodated in thecorresponding bore 155 through wall 154.

As will be clear from FIG. 6, each follower segment 156 is provided witha pair of cup-shaped recesses 169 which are located each on a differentside of bore 156 and open toward wall 154, the recesses having flatbottoms and cylindrical side walls. In each recess, there is disposed ahelical compression spring 170, one end of the spring engaging wall 154and the other end of the spring engaging the bottom of the recess.Springs 170 are held in compression between the follower segments 156and wall 154 and are operative to normally urge the follower segment 156outwardly into the cam groove presented by locking ring 103. Assumingthat the cam groove is positioned to accommodate the follower segments,springs 170 are effective to move the follower and locking segments,coupled together by screws 166, radially outwardly until outer face 153of each locking segment engages the corresponding face of wall 154, asseen in FIG. 5. With the parts in this position, the locking segments147 are fully withdrawn from locking groove 108. Downward movement oflocking ring 103 relative to member 104 causes ca-rn surfaces 137 and138 to ride over the rounded surface portion 161 of the followersegments, until cam surface portion 133 lies in face-to-face engagementwith surface portion 162. With the parts in this position, asillustrated in FIG. 7, the downwardly and inwardly slanting upper faces151 are engaged beneath the upwardly and outwardly slanting wall ofgroove 108 in wedging fashion, so that members 101 and 102 are clampedaxially together with end surfaces 107 and 110 in direct face-to-facecontact with each other.

Referring particularly to FIG. 7, it will be noted that surface portions162 of followers 156 taper inwardly and upwardly at the same angle asdoes surface portion 138 of the cam groove in ring 103. Hence, when thering has been actuated inwardly by downward movement of cam surfaceportion 137 past followers 156, the surface portions 152 come intoflush, faoe-toface engagement with cam surface portion 138. As comparedto the corresponding structure in the embodiment of FIGS. l-4, thefollowers 156, with their specially disposed surface portions 162,afford a greater area of engagement with the cam surface and, therefore,a superior ability to provide a frictional lock-down action for ring103.

When ring 103 is again moved upwardly, so that portion 135 of the camgroove is opposite the follower segments, springs 170 are normallyeffective to urge the follower and locking segments outwardly, causingthe locking segments to be withdrawn from groove 108. Should thesegments be frictionally held or otherwise jammed in place to such anextent that the springs 170 are ineffective to accomplish such movement,the upwardly directed tubular projection 139, located at the bottom ofthe cam groove in ring 1113, moves upwardly between dependent flange160, on the follower segments, and surface 124. As will be clear fromFIG. 7, the parts are so dimensioned that, during such upward movement,the rounded nose 141 of projection 139 engages surface 159 of flange 160and cams the follower segment outwardly, freeing the same so that thesprings 170 will become effective.

Selective actuation of the ring 103, upwardly and downwardly on member104, is accomplished by controlled admission of power fluid underpressure via ducts 134 and 146. With the parts in the relative positionseen in FIG. 5, it will be understood that introduction of power fluidvia duct 134 provides fluid pressure in the expansible chamber definedby shoulder 126, flange 130 and surfaces 125 and 132, this fluidpressure being effective to move the ring 103 downwardly. During suchmovement, any fluid contained within the chamber defined by shoulder121, surfaces 120 and 142, and flange 144 is exhausted via ducts 146. Itwill be obvious that, with the ring 103 in its lowermost position,introduction of power fluid via duct 146 is effective to raise ring 103.

Dependent flange 111 on upper body member 102 presents a downwardly andinwardly tapering frusto-conical surface 171 which opposes surface 106when faces 110 and 107 are in engagement. A suitable metallic sealingCir ring 172, retained by ring 173, provides a fluid-tight seal betweensurfaces 106 and 171 when the upper body member 102 is properly seatedon lower body member 101.

Both embodiments of the invention provide a practical solution to theproblem of establishing by remotely operated means the necessary highaxial clamping force between the wellhead body members, and formaintaining this force throughout the life of the wellhead assembly.Both embodiments also make it possible to employ metal sealing rings,such as the Laurent-type rings 21 and 172, in underwater, remotelyasembled wellhead constructions.

While particularly advantageous embodiments of the invention have beenchosen for illustration, it will be understood by those skilled in theart that various changes and modifications can be made therein withoutdeparting from the scope of the invention as defined in the appendedclaims.

What is claimed is:

1. In a well apparatus for installation at an underwater location, thecombination of an upright lower metal member having an axial throughbore,

a cylindrical outer surface and an outer downwardly directed transverseannular locking shoulder,

a transverse annular upper end face, and

an upwardly exposed annular seat spaced outwardly from said throughbore,

said shoulder, said end face and said seat being concentric with saidthrough bore;

an upright upper metal member having an axial through bore,

a transverse annular lower end face, and

a downwardly exposed annular seat spaced outwardly from said throughbore of said upper member,

said lower end face and said downwardly exposed seat being concentricwith said through bore of said upper member;

dependent tubular means rigidly carried by said upper member concentricwith said through bore thereof; a metal sealing ring; a plurality oflocking devices carried by said dependent tubular means and arranged ina circular series, each of said locking devices having an outer camfollower portion and an inner portion having an upwar ly exposeddownwardly and inwardly slanting surface; means yieldably biasing saidlocking devices outwardly toward positions in which said inner portionsare retracted and said cam follower portions are outwardly exposed; saidupper member being disposed on said lower memher with said end faces indirect mutual engagement and said dependent tubular means surroundingthe upper end portion of said lower member,

said sealing ring being disposed between and engaged by said annularseats,

said locking devices being disposed with said downwardly and inwardlyslanting surfaces facing said locking shoulder;

an annular member carried by said dependent tubular means for axialmovement relative thereto between a first position and a secondposition,

said annular member having inwardly facing cam means comprising a first,sharply tapering frustoconical cam surface and a second adjacentfrusto-conical cam surface, said first and second cam surfaces taperingaxially of said annular member in the same direction, said second camsurface tapering at a markedly smaller angle and being of a smalleraverage diameter than said first cam surface,

movement of said annular member from said first position toward saidsecond position causing said Ti first and second cam surfaces to engagesaid cam follower portions and force said locking devices radiallyinwardly and cause said downwardly and inwardly slanting surfaces of theinner portions of said locking devices to wedge beneath said lockingshoulder and so establish an axial clamping force effective to securesaid upper and lower members rigidly together; and remotely operatedpower means for driving said annu lar member,

the dimensions and locations of said locking shoulder, said secondfrusto-conical cam surface, and said locking devices being such that,when said annular member has been moved axially toward said secondposition to such an extent that the wedging action of said downwardlyand inwardly slanting surfaces beneath said locking shoulder establishessaid axial clamping force, said locking devices are still capable offurther inward movement, as a result of further axial movement of saidannular member, to preserve solid metal-to-metal contact between saidend faces, and between said seats and said sealing ring, even though thewell apparatus has been subjected to vibration, shock and bending forceswhich would otherwise cause loss of such solid metal-to-metal contact.2. Well apparatus according to claim 1, wherein said lower and uppermembers are wellhead members. 3. Well apparatus according to claim 1,wherein said dependent tubular means comprises a generally cylindricalmetal member having an internal diameter such as to closely surroundsaid lower member in the location of said locking shoulder when said endfaces are mutually engaged, said cylindrical metal member having atransverse annular inwardly opening groove,

and a plurality of radial openings extending outwardly from said grooveand spaced apart man annular series, said groove having an upper wallwhich is disposed slightly above said locking shoulder when said endfaces are mutually engaged; and each of said locking devices comprises arigid stem extending through one of said radial openings andinterconnecting said cam follower portion and said inner portion of thelocking device, said inner portion of each of said locking devices beingin the form of an arcuate segment slidably disposed in said inwardlyopening groove, the radial depth of said inwardly opening groove beingsufficiently greater than the radial dimension of said segments to allowsaid segments to be retracted completely within said groove.

4. Well apparatus according to claim-3, wherein said cylindrical metalmember also is provided with an outwardly opening transverse annulargroove,

said radial openings communicating between said inwardly opening andoutwardly opening grooves; and said cam follower portion of each of saidlocking devices is in the form of an arcuate segment slidably disposedin said outwardly opening groove. 5. Well apparatus according to claim4, wherein each of said cam follower segments is provided with anoutwardly facing downwardly and outwardly slanting surface disposed tocome into face-to-face engagement with said second frusto-conicalsurface of said annular member as said annular m mber is moved towardsaid second position. 6. Well apparatus according to claim 3, whereinsaid cylindrical metal member has an intermediate portion of largerouter diameter, and upper and lower portions of smaller outer diameter,

said inwardly opening groove being in said intermediate portion, andsaid radial openings extending outwardly through saidintermediateportion; and said annular member slidably embraces said intermedi ateportion of said cylindrical metal member and includes upper and lowertransverse annular inwardly extending portions which respectivelyembrace said smaller diameter upper and lower portions of said annularmember, said annular member and said cylindrical metal membercooperating to define upper and lower expansible chambers to whichpressure fluid can be supplied selectively to drive said annular member.7. Well apparatus according to claim 1, wherein said seats arefrusto-conical surfaces which converge axially of said upper and lowermembers, and said sealing ring is wedged between said seats.

References Cited by the Examiner I UNITED STATES PATENTS 2,470,2565/1949 McIlroy 285 "3 1 4 4 2,647,798 3/1953 Ballard 285315 2,687,2298/1954 '.Laurent 285--332 2,860,893 11/1958 Clark 285314 2,962,09611/1960 KllOX 285-18 .3,032,125 5/1962 Hiser.

3,050,117 8/1962 Haeber.

3,052,299 9/1962 Geer.

3,062,565 11/ 1962 Word.

3,071,188 1/1963 Raulins 166 66-.6

3,102,591 9/1963 Raulins.

3,147,992 9/1964 Haeber ,28518 CARL} W. TOMLIN, Primary Examiner.

1. IN A WELL APPARATUS FOR INSTALLATION AT AN UNDERWATER LOCATION, THECOMBINATION OF AN UPRIGHT LOWER METAL MEMBER HAVING AN AXIAL THROUGHBORE, A CYLINDRICAL OUTER SURFACE AND AN OUTER DOWNWARDLY DIRECTEDTRANSVERSE ANNULAR LOCKING SHOULDER, A TRANSVERSE ANNULAR UPPER ENDFACE, AND AN UPWARDLY EXPOSED ANNULAR SEAT SPACED OUTWARDLY FROM SAIDTHROUGH BORE, SAID SHOULDER, SAID END FACE AND SAID SEAT BEINGCONCENTRIC WITH SAID THROUGH BORE; AN UPRIGHT UPPER METAL MEMBER HAVINGAN AXIAL THROUGH BORE, A TRANSVERSE ANNULAR LOWER END FACE, AND ADOWNWARDLY EXPOSED ANNULAR SEAT SPACED OUTWARDLY FROM SAID THROUGH BOREOF SAID UPPER MEMBER, SAID LOWER END FACE AND SAID DOWNWARDLY EXPOSEDSEAT BEING CONCENTRIC WITH SAID THROUGH BORE OF SAID UPPER MEMBER;DEPENDENT TUBULAR MEANS RIGIDLY CARRIED BY SAID UPPER MEMBER CONCENTRICWITH SAID THROUGH BORE THEREOF; A METAL SEALING RING; A PLURALITY OFLOCKING DEVICES CARRIED BY SAID DEPENDENT TUBULAR MEANS AND ARRANGED INA CIRCULAR SERIES, EACH OF SAID LOCKING DEVICES HAVING AN OUTER CAMFOLLOWER PORTION AND AN INNER PORTION HAVING AN UPWARDLY EXPOSEDDOWNWARDLY AND INWARDLY SLANTING SURFACE;